Data management for parallel partial discharge monitoring of large GIS fields

Continuous on-line partial discharge monitoring in the UHF range is increasingly used for gas-insulated switchgear (GIS). Generally, due to limited coverage of the UHF signal, a certain number of UHF sensors are required per bay to obtain the overall sensitivity needed. Thus, large GIS fields frequently require hundred or more sensors, in few cases even above three hundred sensors, to be monitored continuously. Generally, the system structure must be scalable to allow adaptation to the different sizes, while maintaining a fully parallel data stream. However, for such true parallel acquisition on hundred or more sensors, an adequate data management is mandatory in order to give timely warnings and to keep track of the history, but without accumulating Gigabytes of data every day. Therefore, acquisition of φ-q-n patterns, storage of trending information, triggering of intensified monitoring, interfacing according to IEC61850, and other tasks need to be carefully planned and preset. Additionally, such installed monitoring system can be used for the acceptance testing of the GIS during commissioning. Here, emphasis is put on vividly displaying oscilloscope-type screens and φ-q-n pattern of freely selectable sensors to quickly identify problems. Based on an installed system, these strategies, their possibilities and limitations are described and discussed. Additionally, examples of typical defects are given.